/*
 * Copyright (c) 2012, Metron, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of Metron, Inc. nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL METRON, INC. BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package com.metsci.glimpse.util.logging;

import java.util.logging.Logger;

/**
 * @author osborn
 */
public final class Stopwatch
{
    private final Logger logger;
    private long startTimeNanos;

    private Stopwatch( Logger logger, String startMessage )
    {
        this.logger = logger;
        restart( startMessage );
    }

    public static final Stopwatch start( Logger logger, String startMessage )
    {
        return new Stopwatch( logger, startMessage );
    }

    public static final Stopwatch start( Logger logger )
    {
        return new Stopwatch( logger, null );
    }

    public static final Stopwatch start( )
    {
        return new Stopwatch( null, null );
    }

    public final void restart( String startMessage )
    {
        if ( startMessage != null && logger != null ) logger.info( startMessage );

        startTimeNanos = System.nanoTime( );
    }

    public final void restart( )
    {
        restart( null );
    }

    public final void info( String message )
    {
        if ( logger != null ) logger.info( formMessage( message ) );
    }

    public final void fine( String message )
    {
        if ( logger != null ) logger.fine( formMessage( message ) );
    }

    public final void finest( String message )
    {
        if ( logger != null ) logger.finest( formMessage( message ) );
    }

    private String formMessage( String root )
    {
        return String.format( root + " (%.0f ms)", 1000 * elapsedSeconds( ) );
    }

    public final double elapsedSeconds( )
    {
        return 1e-9 * getElapsedNanos( );
    }

    private long getElapsedNanos( )
    {
        return System.nanoTime( ) - startTimeNanos;
    }
}
